The present invention relates generally to gasification systems, such as gasification systems used in an integrated gasification combined-cycle (IGCC) power generation plants, and more particularly, to methods and apparatus for optimizing synthetic gas production with a gasification system injection device.
Most known IGCC plants include a gasification system that is integrated with at least one power-producing turbine system. For example, known gasification systems convert a mixture of fuel, air or oxygen, liquid water, and/or steam, and/or CO2 into a synthetic gas, or “syngas”. The syngas is channeled to the combustor of a gas turbine engine, which powers a generator that supplies electrical power to a power grid. Exhaust from at least some known gas turbine engines is supplied to a heat recovery steam generator (HRSG) that generates steam for driving a steam turbine. Power generated by the steam turbine also drives an electrical generator that provides electrical power to the power grid.
At least some known gasification systems associated with IGCC plants produce a syngas fuel by mixing a reactant stream, for example, oxygen, with a slurried carbonaceous material stream, for example, petroleum coke. At least one exothermic reaction is facilitated between the oxygen (O2) and carbonaceous material that produces a syngas that includes hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2). Petroleum coke typically has a relatively low hydrogen content in relation to its carbon content and heat content, thereby increasing gasifier temperatures. Moreover, gasification system components, for example, a gasification reactor refractory, may limit a temperature of reaction, and therefore limit an oxygen-to-carbon ratio, thereby limiting the use of carbon in forming CO and CO2 as well as the associated heat release. The unused carbon is typically incorporated with a slag product, typically in the form of a char or soot, that is either recycled back into the reaction together with a portion of the slag, or is removed from the process with the slag as a waste by-product. The decreased oxygen-to-carbon ratio typically leads to an increased slag and char formation. The combined effect of the above may reduce the gasification system and IGCC plant efficiency with higher operating and capital costs.